<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
</body>
</html>
<script>
    var suibian= (function(){
        function Tank(){
            this.color=''
            this.sudu-0
            this.run=function(){

            }
        }
        var duixiang=null
        return{
            duixianger(){
                if(duixiang){
                    return duixiang
                }
                else{
                    return duixiang=new Tank()
                }
            }
        }
    })()
    var a =suibian.duixianger()
    var b =suibian.duixianger()
    var c =suibian.duixianger()
    console.log(a,b,c);
    console.log(a==b);
</script>